A mixture of Bose and Fermi superfluids

作者:Ferrier Barbut I*; Delehaye M; Laurent S; Grier A T; Pierce M; Rem B S; Chevy F; Salomon C
来源:Science, 2014, 345(6200): 1035-1038.
DOI:10.1126/science.1255380

摘要

Superconductivity and superfluidity of fermionic and bosonic systems are remarkable many-body quantum phenomena. In liquid helium and dilute gases, Bose and Fermi superfluidity has been observed separately, but producing a mixture in which both the fermionic and the bosonic components are superfluid is challenging. Here we report on the observation of such a mixture with dilute gases of two lithium isotopes, lithium-6 and lithium-7. We probe the collective dynamics of this system by exciting center-of-mass oscillations that exhibit extremely low damping below a certain critical velocity. Using high-precision spectroscopy of these modes, we observe coherent energy exchange and measure the coupling between the two superfluids. Our observations can be captured theoretically using a sum-rule approach that we interpret in terms of two coupled oscillators.

  • 出版日期2014-8-29